diff --git a/docs/ref/templates/api.txt b/docs/ref/templates/api.txt index 1955bd4ead..aa386254aa 100644 --- a/docs/ref/templates/api.txt +++ b/docs/ref/templates/api.txt @@ -122,6 +122,10 @@ dot in a variable name, it tries the following lookups, in this order: * Attribute lookup. Example: ``foo.bar`` * List-index lookup. Example: ``foo[bar]`` +Note that "bar" in a template expression like ``{{ foo.bar }}`` will be +interpreted as a literal string and not using the value of the variable "bar", +if one exists in the template context. + The template system uses the first lookup type that works. It's short-circuit logic. Here are a few examples:: diff --git a/docs/topics/templates.txt b/docs/topics/templates.txt index 17e5d6944e..5f6c563312 100644 --- a/docs/topics/templates.txt +++ b/docs/topics/templates.txt @@ -97,6 +97,18 @@ Use a dot (``.``) to access attributes of a variable. * Method call * List-index lookup + This can cause some unexpected behavior with objects that override + dictionary lookup. For example, consider the following code snippet that + attempts to loop over a ``collections.defaultdict``:: + + {% for k, v in defaultdict.iteritems %} + Do something with k and v here... + {% endfor %} + + Because dictionary lookup happens first, that behavior kicks in and provides + a default value instead of using the intended ``.iteritems()`` + method. In this case, consider converting to a dictionary first. + In the above example, ``{{ section.title }}`` will be replaced with the ``title`` attribute of the ``section`` object. @@ -104,6 +116,10 @@ If you use a variable that doesn't exist, the template system will insert the value of the :setting:`TEMPLATE_STRING_IF_INVALID` setting, which is set to ``''`` (the empty string) by default. +Note that "bar" in a template expression like ``{{ foo.bar }}`` will be +interpreted as a literal string and not using the value of the variable "bar", +if one exists in the template context. + Filters =======